The present invention relates to a gas turbine housing component comprising a wall structure, wherein the wall structure comprises two adjacent wall parts and a connection arrangement arranged between adjacent edges of the two wall parts. The invention is further directed to a gas turbine engine, and especially to an aircraft engine, comprising the component. Thus, the invention is especially directed to a jet engine.
Jet engine is meant to include various types of engines, which admit air at relatively low velocity, heat it by combustion and shoot it out at a much higher velocity. Accommodated within the term jet engine are, for example, turbojet engines and turbofan engines. The invention will below be described for a turbofan engine, but may of course also be used for other engine types.
An aircraft gas turbine engine of the turbofan type generally comprises a forward fan and booster compressor, a middle core engine, and an aft low pressure power turbine. The core engine comprises a high pressure compressor, a combustor and a high pressure turbine in a serial relationship. The high pressure compressor and high pressure turbine of the core engine are interconnected by a high pressure shaft. The high-pressure compressor is rotatably driven to compress air entering the core engine to a relatively high pressure. This high pressure air is then mixed with fuel in the combustor and ignited to form a high energy gas stream.
The gas stream flows aft and passes through the high-pressure turbine, rotatably driving it and the high pressure shaft which, in turn, rotatably drives the high pressure compressor.
The gas stream leaving the high pressure turbine is expanded through a second or low pressure turbine. The low pressure turbine rotatably drives the fan and booster compressor via a low pressure shaft. The low pressure shaft extends through the high pressure rotor. Most of the thrust produced is generated by the fan.
Annular gas turbine housing components are adapted to define the primary gas flow channel through the engine and other annular compartments in the engine. Such annular compartments have different purposes and often have different internal pressure during operation. The wall parts may be formed by castings. Different wall parts are interconnected in order to form the component and finally the engine. Depending on the position of such walls, they are subjected to a high thermal load during operation. This may lead to a thermal distortion between the connected walls during operation. Further, due to the temperature environment, high temperature alloys are used, which are difficult to machine by conventional methods. Adjacent wall parts have traditionally been interconnected via bolted connections.
It is desirable to achieve a gas turbine housing component comprising a wall structure, which creates conditions for an improved connection between interconnected walls with regard to sealing. The component should further be cost-efficient in production while maintaining or improving its operational characteristics.
According to an aspect of the present invention, a connection arrangement comprises an elongated seal strip positioned along the wall part edges and bridging the distance between the wall part edges.
Especially, an aspect of the invention allows for sliding between the wall parts during operation which is necessary in the temperature application due to the thermal expansion.
Further, the invention has multiple seal surfaces. It is particularly preferred for designs with a lateral joint between the wall parts. Further, an aspect of the invention creates conditions for simplified machined fairing castings.
Preferably, the seal strip is positioned in an overlapping state relative to both wall parts. Further, the seal strip is adapted to contact the wall parts in a sealing manner.
According to a preferred embodiment, the connection arrangement comprises a support means, which is connected to the seal strip and adapted to hold the seal strip in the position along the wall part edges, and that the seal strip and the support means contact the wall parts on opposite sides thereof. By this arrangement, the seal strip may be pressed against the wall part edges by means of the support means, wherein the sealing function is improved.
According to a further preferred embodiment, the support means comprises at least one elongated support strip. This embodiment creates conditions for using a minimum number of parts in order to seal between the wall parts. The seal strip and the support strip are preferably interconnected so that a gap between the wall parts is enclosed and sealed.
The support strip preferably forms a flexible element, i.e a spring element. Preferably, the support means and the seal strip are connected in such a manner that the seal strip is pressed against both wall parts.
According to a further preferred embodiment, the seal strip comprises a first portion bridging the distance between the wall part edges on a first side of the wall parts and a second portion projecting from the first portion between the wall part edges, preferably to a position on a second side of the wall parts. The second portion of the seal strip is thereby exposed to the other side of the wall parts and thereby available for connection to the support means.
According to a further development of the last mentioned embodiment, the support means comprises at least one through hole, and a part of the second portion of the seal strip extends through said hole. This design creates conditions for an efficient connection (and sealing contact) between the seal strip and the support means. Preferably, the second portion of the seal strip comprises at least two fingers, which act on the support means on opposite sides of the through hole. This creates conditions for a central positioning of the seal strip with regard to the support means and the gap between the wall parts.
Other advantageous features and functions of various embodiments of the invention are set forth in the following description.